If generation names like "Baby Boomers" and "Generation X" are just a short way of referring to people born during certain intervals, you can use them without implying that these categories have any meaningful properties.

But if these names are supposed to refer to generations with identifiable characteristics, we can test whether these generations exist. In this notebook, I suggest one way to formulate generations as a claim about the world, and test it.

Suppose we take a representative sample of people in the U.S., divide them into cohorts by year of birth, and measure the magnitude of the differences between consecutive cohorts. Of course, there are many ways we could define and measure these differences; I'll suggest one in a minute.

But ignoring the details for now, what would those difference look like if generations exist? Presumably, the differences between successive cohorts would be relatively small within each generation, and bigger between generations.

If we plot the cumulative total of these differences, we expect to see something like the figure below (left), with relatively fast transitions (big differences) between generations, and periods of slow change (small differences) within generations.

On the other hand, if there are no generations, we expect the differences between successive cohorts to be about the same. In that case the cumulative differences should look like a straight line, as in the figure below (right):

So, how should we quantify the differences between successive cohorts. When people talk about generational differences, they are often talking about differences in attitudes about political, social issues, and other cultural questions. Fortunately, these are exactly the sorts of things surveyed by the General Social Survey (GSS).

To gather data, I selected question from the GSS that were asked during the last three cycles (2010, 2012, 2014) and that were coded on a 5-point Likert scale.

You can see the variables that met these criteria, and download the data I used, here:

Conclusion: Using this set of questions from the GSS, and two measures of divergence, it seems that the total divergence between successive cohorts is nearly constant over time.

If a "generation" is supposed to be a sequence of cohorts with relatively small differences between them, punctuated by periods of larger differences, this study suggests that generations do not exist.

3 comments:

Interesting approach! My first instinct would have been to plot age on the x-axis and an index of social and political attitudes on the y-axis, fit a spline, and examine jumps at the lower and upper bounds of each generational interval. I wonder if this would produce different results.